Advanced Information and Commands

Overview

This page contains advanced AFS commands and the options you can use with them, plus examples on how to use some of them.

fs --- File Commands

Some fairly useful commands:

• Check which servers are down: fs checkservers
• Obtaining the Cache Size: fs getcacheparms
• Flushing Files: fs flush filename
• Brief Volume Information: fs lq path
• Find Volume Information: fs whereis path

pts --- Group Commands

vos --- Server Commands

Some fairly useful commands:

• Listing Volume Attributes: vos examine [volume], i.e. vos examine user.frank or even vos examine user. frank.backup
• Listing Partition Info: vos partinfo
• Volume Info: vos examine sun4c_411.pubsw.bin
  (after finding the exactly name from fs lq /usr/pubsw/bin

kas --- System Administration Commands

More file permissions

The files contained within your AFS home directory use both AFS and Unix file permissions. The only Unix (NFS) permissions which are still applicable under AFS, however, are permissions for the user. Unix permissions on directories are not used.

value -- permission code

400 -- r (Read)

Allows user with AFS read access (rl) to the directory to read or copy the file.

200 -- w (Write)

Allows user with AFS write access (wl) to modify or overwrite a file. Does NOT determine whether a user can delete the file, however. AFS delete (d) permission on the directory does that.

100 -- x (Execute)

Allows user with AFS read access (rl) to execute the file

For example, to give read and execute permission to a file named [filename], type either of the following:
chmod 500 [filename]
chmod u+rx [filename]

The first command uses the numeric code (read + execute = 400 + 100 = 500); the second command uses the letter code (user plus read execute).

For more info on Unix permissions, read the man page for chmod (type "man chmod") and ls. The command "ls -l" will display the Unix permissions for the files. The command "fs la" will display the AFS permissions for the files. They are not the same thing.

Mounting volumes to recover files

Between midnight and 3 AM each night, a backup image of your account is made. If you delete or modify a file in an AFS volume, you may be able to retrieve the file if it existed when the backup image was made. NOTE: Under most circumstances, you should be able to just go into your .backup directory and copy whatever file you need from there directly, without going through the following steps. However, sometimes the volume containing the backup is not mounted. If this is the case, the command:

fs mkmount ~/.backup user.$USER.backup

will mount your backup volume in the directory named .backup in your home directory. You can use a name other ~/.backup if you want. To unmount the volume, type:

fs rmmount ~/.backup

You don't need to unmount it: files in .backup do not count against your disk quota usage.

The backup volume (user.$USER.backup) is a read-only copy of your account. You cannot remove or alter files in the backup volume, and file changes made after the last backup but before the next backup are not available. To restore a file, you must copy the file from the backup volume to your account.

Suppose you delete the file ~/Mail/incoming. The following commands may recover it (assuming you have sufficient quota and you do it in time):

cd
fs mkmount ~/.backup user.$USER.backup
cp ~/.backup/Mail/incoming ~/Mail/incoming.bak
fs rmmount ~/.backup

The recovered file would be named incoming.bak in the Mail directory.

Groups

Maintaining groups -- Using the pts command

One neat thing about AFS is that you can create your own groups and grant permissions for individual AFS usernames. To be in a group or individually listed in an ACL, a person needs to have a SUNet ID.

The command pts and its suite of subcommands allows you to create your own groups. Suppose your SUNet ID was "sunetid". Here is a list of common pts commands:

Creates a private group named sunetid:groupname
pts creategroup sunetid:groupname

Adds a user to the group sunetid:groupname (you must own the group)
pts adduser [username] sunetid:groupname

Remove user from the group sunetid:groupname
pts removeuser [username] sunetid:groupname

Delete the group sunetid:groupname from existence
pts delete sunetid:groupname

For a given directory, you can add a group to the acl. For example:
fs sa project sunetid:project read

pts Help, Shortcuts, And Tidbits

As expected, the pts commands have help options and abbreviations. See the man page for pts. You can also type:

Other useful pts commands are:

File system layout

Paths in AFS

• /afs - base of AFS file system
• /afs/ir.stanford.edu (/afs/ir) - base of our cell
• /afs/ir/pubsw - campus software packages
• /afs/ir/systems - OS mount points
• /afs/ir/class - academic file space
• /afs/ir/group - organization file space
• /afs/ir/users - personal account space

/usr/pubsw

$ cardinal1:~ > ls /usr/pubsw

$ ls /usr/pubsw/package

Common sysnames (@sys)

• sun4x_58: Sun Solaris 8 (elaine, epic, saga, amy, fable, junior, tree).
• i386_linux24: Linux 2.4 kernel (firebird, raptor, cardinal).
• hpux_110: HP-UX 11.0 (pubsw & afs support)
• rs_aix43: IBM AIX 4.3 (pubsw & afs support)
• alpha_dux40: Digital Unix 4.0 (pubsw & afs support)